/*
	FreeRTOS.org V4.2.1 - Copyright (C) 2003-2007 Richard Barry.

	This file is part of the FreeRTOS.org distribution.

	FreeRTOS.org is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	FreeRTOS.org is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with FreeRTOS.org; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

	A special exception to the GPL can be applied should you wish to distribute
	a combined work that includes FreeRTOS.org, without being obliged to provide
	the source code for any proprietary components.  See the licensing section 
	of http://www.FreeRTOS.org for full details of how and when the exception
	can be applied.

	***************************************************************************
	See http://www.FreeRTOS.org for documentation, latest information, license 
	and contact details.  Please ensure to read the configuration and relevant 
	port sections of the online documentation.

	Also see http://www.SafeRTOS.com for an IEC 61508 compliant version along
	with commercial development and support options.
	***************************************************************************
*/

/* 

Changes between V2.5.1 and V2.5.1

	+ The memory pool has been defined within a struct to ensure correct memory
	  alignment on 32bit systems.

Changes between V2.6.1 and V3.0.0

	+ An overflow check has been added to ensure the next free byte variable 
	  does not wrap around.
*/


/*
 * The simplest possible implementation of pvPortMalloc().  Note that this
 * implementation does NOT allow allocated memory to be freed again.
 *
 * See heap_2.c and heap_3.c for alternative implementations, and the memory
 * management pages of http://www.FreeRTOS.org for more information.
 */
#include <stdlib.h>
#include "FreeRTOS.h"
#include "task.h"

/* Setup the correct byte alignment mask for the defined byte alignment. */

#if portBYTE_ALIGNMENT == 8
#define heapBYTE_ALIGNMENT_MASK ( ( size_t ) 0x0007 )
#endif

#if portBYTE_ALIGNMENT == 4
#define heapBYTE_ALIGNMENT_MASK	( ( size_t ) 0x0003 )
#endif

#if portBYTE_ALIGNMENT == 2
#define heapBYTE_ALIGNMENT_MASK	( ( size_t ) 0x0001 )
#endif

#if portBYTE_ALIGNMENT == 1
#define heapBYTE_ALIGNMENT_MASK	( ( size_t ) 0x0000 )
#endif

#ifndef heapBYTE_ALIGNMENT_MASK
#error "Invalid portBYTE_ALIGNMENT definition"
#endif

/* Allocate the memory for the heap.  The struct is used to force byte
alignment without using any non-portable code. */
static struct xRTOS_HEAP
{
  unsigned portLONG ulDummy;
  unsigned portCHAR ucHeap[configTOTAL_HEAP_SIZE];
} xHeap;

static size_t xNextFreeByte = (size_t) 0;
/*-----------------------------------------------------------*/

void *
pvPortMalloc (size_t xWantedSize)
{
  void *pvReturn = NULL;

  /* Ensure that blocks are always aligned to the required number of bytes. */
#if portBYTE_ALIGNMENT != 1
  if (xWantedSize & heapBYTE_ALIGNMENT_MASK)
    {
      /* Byte alignment required. */
      xWantedSize +=
	(portBYTE_ALIGNMENT - (xWantedSize & heapBYTE_ALIGNMENT_MASK));
    }
#endif

  vTaskSuspendAll ();
  {
    /* Check there is enough room left for the allocation. */
    if (((xNextFreeByte + xWantedSize) < configTOTAL_HEAP_SIZE) && ((xNextFreeByte + xWantedSize) > xNextFreeByte))	/* Check for overflow. */
      {
	/* Return the next free byte then increment the index past this
	   block. */
	pvReturn = &(xHeap.ucHeap[xNextFreeByte]);
	xNextFreeByte += xWantedSize;
      }
  }
  xTaskResumeAll ();

  return pvReturn;
}

/*-----------------------------------------------------------*/

void
vPortFree (void *pv)
{
  /* Memory cannot be freed using this scheme.  See heap_2.c and heap_3.c 
     for alternative implementations, and the memory management pages of 
     http://www.FreeRTOS.org for more information. */
  (void) pv;
}

/*-----------------------------------------------------------*/

void
vPortInitialiseBlocks (void)
{
  /* Only required when static memory is not cleared. */
  xNextFreeByte = (size_t) 0;
}
